Collapsible shelf unit



FIG. 1 is a perspective view of a collapsible shelf unit showing the ornamental design of the invention.

FIG. 2 is a perspective view from the front of the ornamental design of the collapsible shelf unit of the invention.

FIG. 3 is a perspective view from the back of the ornamental design of the collapsible shelf unit of the invention.

FIG. 4 is a side elevational view from the right side of the ornamental design of the collapsible shelf unit of the invention. The left side is a mirror image of the FIG. 4.

FIG. 5 is a top plan view of the ornamental design of the collapsible shelf unit of the invention; and,

FIG. 6 is a bottom plan view of the ornamental design of the collapsible shelf unit of the invention. 

I claim the ornamental design for a collapsible shelf unit, as shown and described. 